1. Technical Field
The present invention relates to a projector that projects an image light flux modulated by a light modulator including a liquid crystal panel and a structural birefringent polarization separation element.
2. Related Art
There is a projector having a wire-grid polarization separation element disposed in a position facing a reflective liquid crystal panel with the wire-grid polarization separation element inclined to the optical axis by 45 degrees (see JP-A-2008-275798). In the projector, polarized light passing through the wire-grid polarization separation element is incident on the reflective liquid crystal panel, and the light modulated by and reflected off the reflective liquid crystal panel is reflected off the wire-grid polarization separation element. In this way, the reflected polarized light is separated from the incident polarized light.
There is another projector including a diaphragm mechanism having pivotal light-blocking members that adjust the amount of attenuation of an illumination light flux (see JP-A-2006-308787). In this projector, slit-shaped openings or any other suitably shaped openings are formed in each of the light-blocking members so that part of the illumination light flux passing through the light-blocking members is relatively uniform even when the degree of blockage of the illumination light flux is the highest.
In the projector described in JP-A-2008-275798, however, improvement in contrast of a projected image is insufficient because no consideration is given to the angular distribution of the illumination light flux. That is, the present inventor has ascertained that the angular distribution of the illumination light flux affects the contrast of a projected image in the projector using a wire-grid polarization separation element described in JP-A-2008-275798 and found that the contrast may still be improved when the angular distribution of the illumination light flux is set appropriately.
In the projector described in JP-A-2006-308787, on the other hand, the uniformity of the illumination light is relatively readily maintained in a light level adjustment process, but the contrast of a projected image is not always readily maintained or improved.